Showing papers by "Cranfield University published in 1991"
TL;DR: In this article, the Harten-Lax-van Leer (HLLE) scheme is positively conservative under certain conditions on the numerical wavespeeds, and this observation allows the linearised schemes to be rescued by modifying the wave-peeds employed.
896 citations
TL;DR: In this article, a review of the generation of shear forces by pneumatic tyres under steady state conditions is presented, in a practical context, through reference to the uses to which models may be put by the vehicle dynamicist and the tyre designer.
Abstract: SUMMARY Modelling of the generation of shear forces by pneumatic tyres under steady state conditions is reviewed. The review is placed in a practical context, through reference to the uses to which models may be put by the vehicle dynamicist and the tyre designer. It will be of interest also to the student of rolling contact problems. The subject is divided into sections, covering physically founded models which require computation for their solution, physically based models which are sufficiently simplified to allow analytical solutions and formula based, empirical models. The classes are more nearly continuous than this strict division would imply, since approximations in obtaining analytical solutions may be made, empirical correction factors may be applied to analytical results and formula based methods may take into account tyre mechanical principles. Such matters are discussed in the relevant sections. Attention is given to the important matter of choosing model parameters to best represent the beha...
367 citations
TL;DR: Group technology is a method of organization for factories in which organizational units each complete a particular set or “family” of parts with no backflow, or crossflow between groups, and are equipped with all the facilities they need to do so.
310 citations
TL;DR: In this paper, a review of theoretical and numerical studies of VLF triggered emissions generated by manmade signals propagating in the whistler mode in the magnetosphere is presented.
246 citations
TL;DR: A relatively simple printed sensor, based on 7,7,8,8-tetracyano quinodimethane-modified graphite and immobilised butyrylcholinesterase, which operated at a potential of 100 mV versus Ag/AgCl (printed) and was sensitive to inhibition by organophosphates.
130 citations
TL;DR: In this paper, the authors argue that there are trends currently present in industry and management which require human resource managers to have much higher levels of competence and skills and that concepts and techniques from marketing can provide means by which HR managers can be more effective.
128 citations
125 citations
TL;DR: In this paper, a critical but speculative review considers the detailed implications of operating enzyme electrodes in organic solvents and briefly examines the broader issues of optical, calorimetric and piezoelectric transduction coupled with both catalytic and affinity systems, such as nucleic acid probes and antibodies.
113 citations
TL;DR: An amperometric enzyme electrode incorporating horseradish peroxidase for the determination of hydrogen peroxide in organic solvents was described in this article, where the enzyme was co-adsorbed with an electron mediator, potassium hexacyanoferrate(II), on the surface of a graphite foil electrode.
102 citations
01 Jan 1991
TL;DR: In this paper, the authors describe a modeling framework within which such distinct elements as the soot formation mechanism and the turbulence-radiation interaction can be evaluated, and use flamelet modelling to both simplify the chemistry, by comparison between detailed prediction and laminar experiment, and to address the issue of turbulence interaction in the buoyant fire computations.
Abstract: The processes of soot formation and thermal radiation in turbulent non-premixed flames are intimately coupled. The comprehensive modelling of fluctuating scalar properties in buoyantly-driven fires, necessary for the detailed prediction of the soot and radiation fields, is then a particularly challenging problem. This paper describes a modelling framework within which such distinct elements as the soot formation mechanism and the turbulence-radiation interaction can be evaluated. Flamelet modelling is used to both simplify the soot chemistry, by comparison between detailed prediction and laminar experiment, and to address the issue of turbulence interaction in the buoyant fire computations. Predictions of spectrally-resolved radiative emission at visible and infra-red wavelengths in a methane-fueled fire are compared with radiometer measurements.
98 citations
TL;DR: In this paper, the screening process undertaken to choose the most suitable expansion machine for a steam Rankine-cycle engine, operating principally as a ‘mini’ combined heat and power unit, is described.
01 Sep 1991
TL;DR: In this article, the authors considered the use of subjective techniques for the evaluation of aerospace system design evaluation and found that subjective techniques were useful for both workload and situational awareness (SA) considerations.
Abstract: Both workload and situational awareness (SA) have been recognised as important considerations in aerospace system design evaluation. This paper considers the use of subjective techniques for the me...
TL;DR: In this paper, the authors investigated factors associated with the perceptions of stress reported by nurses in a general hospital environment in the UK, and found that the levels and sources of stress experienced by nursing staff were examined in relation to the type of ward or department, and nursing grade.
Abstract: This study investigated factors associated with the perceptions of stress reported by nurses in a general hospital environment in the UK. The levels and sources of stress experienced by nursing staff were examined in relation to the type of ward or department, and nursing grade. The association between reported stress and job satisfaction was also examined. By means of a self-completion questionnaire survey, data were collected from 234 nurses from 24 wards in a single general hospital. The Brayfield and Rothe job satisfaction index was used to provide data for analysis. Factor analysis, analysis of variance, and Pearson product moment correlation procedures were performed on these data. The factor analysis identified two main factors concerned with sources of stress: interpersonal relations and resource problems, and dealing with death. Although there were no differences found across wards, the analyses of variance revealed that reported stress varied over different nursing grades. It was also f...
01 Jan 1991
TL;DR: This chapter presents a study that explores the relationships between the primary structure, conformation, and physical properties of three new commercial polymers from microbial fermentation, gellan, welan, and rhamsan.
Abstract: Publisher Summary Following the spectacular commercial success of their first bacterial polysaccharide xanthan, Kelco (now a Division of Merck) has developed three new commercial polymers from microbial fermentation—namely, gellan, welan, and rhamsan. This chapter presents a study that explores the relationships between the primary structure, conformation, and physical properties of these materials. Gellan gum is a deacylated form of the extracellular bacterial polysaccharide from Auromonas elodea (ATCC 31461). In the native form, it has an L-glyceryl substituent on O-2 of the 3-linked glucose and an acetyl group on approximately half of the O-6 atoms of the same residue, but both these groups are lost during normal commercial extraction. Welan, from Alcaligenes ATCC 31555 (formerly known as S-130), has the same backbone sequence as gellan, but with a monosaccharide side chain at O-3 of the 4-linked glucose; this can be either α-L-rhamnose or a-L-mannose, in the approximate ratio 2:1. Welan does not gel, but forms viscous solutions that can suspend particles or stabilize emulsions in a manner similar to xanthan “weak gels.” These properties are stable to high temperatures and the polymer is intended primarily for commercial use in oil recovery. Rhamsan, the exopolysaccharide from Alcaligenes ATCC 31961 (formerly known as S-194), is also a branched variant of gellan.
TL;DR: In this paper, the authors present a framework for formulating and reviewing an after-sales support strategy and link it to a manufacturing strategy model to produce a comprehensive strategy for customer satisfaction over the lifetime of a manufactured product.
Abstract: For some time there have been models for considering manufacturing strategy which focus on the product but which essentially ignore dimensions of aftersales support. This article presents a framework for formulating and reviewing an after‐sales support strategy and links it to a manufacturing strategy model to produce a comprehensive strategy for customer satisfaction over the lifetime of a manufactured product.
TL;DR: Organizational status changes in the direction of privatization do not appear to guarantee improved performance and the impact of these organizational status changes on financial performance measured using a set of standard financial ratios is examined.
Abstract: In recent years there has been worldwide interest in ‘privatization’ and transferring government department functions to quasi-autonomous agencies. This paper presents the results of a study of 10 organizations in the U.K. which underwent changes in their organizational status within government or which crossed the public-private boundary. The focus of the study is the impact of these organizational status changes on financial performance measured using a set of standard financial ratios. These ratios did not provide a consistent set of statistically significant results. Organizational status changes in the direction of privatization do not appear to guarantee improved performance.
TL;DR: In this paper, a unified theory of strategic manufacturing management is proposed to facilitate the preparation of a development plan which will not only enable manufacturing to support the competitive strategy of the firm but also to establish a strategy for manufacturing-led competitive advantage.
Abstract: There is a need for a unified theory of the strategic management of manufacturing. Current theory encourages the strategic management of manufacturing by seeking to match the use of production resources with the need to satisfy the order winning criteria of the target markets. Such an approach suggests but one strategic role of manufacturing. The purpose of this article is to use previous research findings on a taxonomy of generic manufacturing strategies, the author′s own research and recently published academic theory to propose a unified theory of strategic manufacturing management. The theory links competitive strategy with four strategic roles of manufacturing. A strategic planning model is proposed to facilitate the preparation of a development plan which will not only enable manufacturing to support the competitive strategy of the firm but also to establish a strategy for manufacturing‐led competitive advantage.
TL;DR: In this paper, simple, strip-type sensors based on 7,7,8,8-tetracyanoquinodimethane-modified graphite were prepared using screen printing techniques.
01 Jan 1991
TL;DR: The amino acid sequence of this superoxide dismutase from the trematode Schistosoma mansoni shares many features of cytosolic Cu/Zn superoxide Dismutase, including 20 of the 21 invariant residues found in 19 Cu/ Zn enzymes, suggesting a similar type of beta-barrel fold and active site structure for the extracellular enzyme.
Abstract: Copper/zinc superoxide dismutase is typically an enzyme of eukaryotes. The presence of the enzyme in the ponyfish symbiont Photobocterium leiognothi and some free living bacteria does not have an immediate explanation. Amino acid sequence alignment of 19 Cu/Zn superoxide disrnutases shows 21 invariant residues in key positions related to maintenance of the β-barrel fold, the active site structure including the electrostatic channel loop, and dimer contacts. Nineteen other residues are invariant in 18 of the 19 sequences. Thirteen of these nearly invariant residues show substitutions in Photobocterium Cu/Zn superoxide dismutase. Copper/zinc superoxide disrnutase from the trematode Schisiosoma mansoni shows an N-terminal sub-domain with a hydrophobic leader peptide. as in human extracellular superoxide dismutase which is a Cu/Zn enzyme. The latter also has a C-terminal sub-domain with preponderance of hydrophilic and positively charged residues. The amino acid sequence of this superoxide dismutase between t...
TL;DR: In this paper, an enzyme electrode was described for the determination of cholesterol dissolved in chloroform/hexane (1:1), which was shown to be applicable to the detection of cholesterol in samples of butter and margarine.
Abstract: An enzyme electrode is described for the determination of cholesterol dissolved in chloroform/hexane (1:1). The enzyme electrode is shown to be applicable to the determination of cholesterol in samples of butter and margarine.
TL;DR: In this article, the authors describe how inclusion of a polyetherimide (PEI) thermoplastic rich phase can significantly toughen the epoxy resin without a fall in apparent stiffness, which accompanies the more traditional method of rubber toughening.
Abstract: Highly crosslinked, brittle epoxy resin based on tetraglycidyl-4,4′-diaminodiphenyl methane (TGDDM) cured with 4,4′-diaminodiphenyl sulphone (DDS) is widely used as a matrix material for aerospace composite applications. This work describes how inclusion of a polyetherimide (PEI) thermoplastic rich phase can significantly toughen the resin without a fall in apparent stiffness, which accompanies the more traditional method of rubber toughening. Dynamic mechanical analysis and scanning electron microscopy are used to characterize morphology, while fracture toughness and flexural modulus measurements are also performed on the cured resins. The extent of toughening is found to be dependent upon PEI concentration and test temperature. It is observed that the PEI rich phase toughens through ductile drawing across the faces of the advancing crack tip, and that this is the dominant toughening mechanism in the material.
TL;DR: The marketing planning process appears on the surface to be just a series of procedural steps, but it does in fact embrace a set of underlying values and assumptions as discussed by the authors, and only the more developed and mature organizations seem likely to have the corporate culture which is capable of sustaining these values.
Abstract: This paper examines the marketing planning process of a number of British Companies. It finds that the companies who subscribe to what is described in the paper as a “complete marketing planning process”, are further along an organizational evolutionary development path than their semi‐planning and non‐planning counterparts. While the marketing planning process appears on the surface to be just a series of procedural steps, it does in fact embrace a set of underlying values and assumptions. Only the more developed and mature organizations seem likely to have the corporate culture which is capable of sustaining these values. Corporate culture is often intangible to the outsider, but can be very real to those within the company. It develops partly through the way the company has triumphed over adversity in the past, and partly through the so‐called “culture carriers”. These are the influential figures who, by their behaviour, communicate the organizational values they wish to see espoused. Because marketing...
TL;DR: It is shown that mucus gels from the colon and small intestine have similar mechanical behaviour and properties to those from the stomach and duodenum, and the caution that should be exercised when interpreting the rheological properties of mucus preparations, particularly with respect to their content of mucosal cellular material is stressed.
TL;DR: In this article, the relationship between ownership and performance was tested on ten UK organizations which had undergone status change, within the public sector or between the public and private sectors, in the last twenty years.
Abstract: Hypotheses derived from the public choice and other literatures on the relationship between ownership and performance were tested on ten UK organizations which had undergone status change, within the public sector or between the public and private sectors, in the last twenty years. Results on tests of performance in productivity, employment, and financial ratios against change in status, competition and internal management failed in most cases to support the thesis that change in ownership improves enterprise performance, even in its more sophisticated form where ownership change is assumed to be accompanied by increased competition and improved managerial incentives.
TL;DR: In this article, a commercial low-profile additive containing acidterminated poly(vinyl acetate) (PVAc) was added, at concentrations of 0-16 wt%, to a solution of unsaturated polyester resin in styrene.
TL;DR: Improvements are required in biosensor design and performance before they become widely accepted in industrial process monitoring, but as the biotechnology industry expands, biosensors may become more acceptable because they are the only devices capable of delivering the information required.
TL;DR: The Savonius rotor can develop a relatively high torque at low rotational speeds and is cheap to build, but it harnesses only a small fraction of the wind energy incident upon it as mentioned in this paper.
TL;DR: In this paper, a Wankel expander was selected as the most appropriate device for a steam Rankine engine, operating principally, as a mini combined heat-and-power unit with a mechanical power output of 5-20 kW.
TL;DR: In this paper, an approximate linearized Riemann solver for the time-dependent Euler equations is presented. But the linearized solver is not suitable for solving general initial-value problems.
Abstract: The time-dependent Euler equations of gas dynamics are a set of nonlinear hyperbolic conservation laws that admit discontinuous solutions (e. g. shocks). In this paper we are concerned with Riemann-problem-based numerical methods for solving the general initial-value problem for these equations. We present an approximate, linearized Riemann solver for the time-dependent Euler equations. The solution is direct and involves few, and simple, arithmetic operations. The Riemann solver is then used, locally, in conjunction with the weighted average flux numerical method to solve the time-dependent Euler equations in one and two space dimensions with general initial data. For flows with shock waves of moderate strength the computed results are very accurate. For severe flow regimes we advocate the use of the present linearized Riemann solver in combination with the exact Riemann solver in an adaptive fashion. Numerical experiments demonstrate that such an approach can be very successful. One-dimensional and two-dimensional test problems show that the linearized Riemann solver is used in over 99% of the flow field producing net computing savings by a factor of about 2. A reliable and simple switching criterion is also presented. Results show that the adaptive approach effectively provides the resolution and robustness of the exact Riemann solver at the computing cost of the simple linearized Riemann solver. The relevance of the present methods concerns the numerical solution of multi-dimensional problems accurately and economically.